A prior-art retainer clip shall now be described by way of FIG. 1, FIG. 2, and FIG. 3.
FIG. 1 is a perspective view, showing the condition of attachment of a prior-art retainer clip, FIG. 2 is a perspective view, showing the prior-art retainer clip, and FIG. 3 is a perspective view, showing a prior-art key cylinder.
Inserted parts 106 of a retainer clip 105 with a substantially C-like planar shape are inserted into cylinder slits 104 provided in large and small anti-rotation protrusions 103 that are respectively formed in pairs on side end parts of a flange part 102 of a key cylinder 101, and the key cylinder was attached to an automotive body panel by the press-contacting of raised parts 107 formed on the inserted parts against cylinder slit upper parts 108. In FIG. 2, symbol 109 indicates a hook that is provided for preventing the falling-off of the attached retainer clip.
However, with the prior-art retainer clip, there was a problem in that since the width (symbol B in FIG. 3) of each of the anti-rotation protrusions formed on the side end parts of the flange part of the key cylinder is smaller than the width (symbol A in FIG. 2) of each of the inserted parts and only a part of each inserted part is thus press-contacted against the corresponding anti-rotation protrusion, when a deforming force is applied directly or indirectly to the key cylinder by a screwdriver or other illicit unlocking tool, the inserted parts became turned in the directions of symbols C in FIG. 2, causing the press-contacting of the inserted parts and anti-rotation protrusions to become disengaged, the retainer clip to fall off, and the key cylinder to become removed from the automotive body panel.
Though a means, wherein the inserted parts are made small in width so that the entire inserted parts are put in pressed contact against the anti-rotation protrusions, may be considered in regard to the above problem, with such a means, though the turning of the inserted parts can be prevented, the inserted parts can slide in transverse directions (directions indicated by symbol D in FIG. 2) to cause the retainer clip to fall off and the key cylinder to become removed from the automotive body panel.
Though a means, wherein the inserted parts are made thick in plate thickness, may be considered for the prevention of sliding, such a means is not necessarily feasible in consideration of the requirement that, in the process of attaching or removing a retainer clip, the work be done within a fixed range of force.